Core plug



Dec. 31, 1963 A. BEAUDOlN 3,115,969

CORE PLUG Filed Aug. 2. 1961 INVENTQR Andre BEAUDO/N BY r f W AGEMZL United States Patent 3,115,969 CORE PLUG Andr Beaudoiu, Dosquet, Lotbiniere County, Quebec, Canada Filed Aug. 2, 1961, Ser. No. 128,836 Claims priority, application Canada Sept. 29, 1960 Claims. (Cl. 206-59) The present invention relates to core plugs, and more particularly to an improved core plug of the type which is used for insertion into the hollow core of newsprint paper rolls or other like rolls of paper, and of other materials, and which is a complement to the core plug described and claimed inU.S. Patent No. 2,985,292, dated May 23, 1961 of the same inventor.

The core plug of the present invention is more particularly adapted to be used in conjunction with cores of greater diameter than the plug described and claimed in the above noted patent.

It is known that paper rolls and more particularly newsprint paper rolls are normally provided with a hollow core made of carboard or other substantially soft material; the ends of the core are normally protected against damage by a plug generally made of wood for protection during handling and shipping. These plugs are made of wood because they must be of very low cost, but as wood contracts during drying, it is known that conventional wooden plugs pop out of the core and become lodged between the wrapping paper and the paper roll itself especially when the paper rolls are subjected to a compression force due to piling of the rolls one on top of the other. When a newsprint paper roll, the plugs of which are thus dislodged, is put upright, the plugs cause considerable damage to the paper and often ruin the roll almost completely. This is a very important problem in the newsprint paper industry.

The core plug in accordance with the above noted US. patent solves this problem when used in association with cores of relatively small internal diameter but this plug is too expensive for use in association with larger internal diameter cores. This is due to the fact that in the above noted patent, the resilient wires extend longitudinally of the plug body and the latter must have a relatively important minimum length whereby, with increase in diameter, the amount of wood used for each plug becomes excessive.

The ge-neral object of the present invention resides therefore in the provision of a core plug of the character described which is provided with means for preventing the plug from popping out of the core.

A more specific object of the present invention resides in the provision of a plug of the character described wherein the retaining means are so disposed on the plug that the latter can be manufactured with a minimum length.

Another object of the present invention resides in the provision of a plug of the character described, more particularly adapted for use with cores having a substantial internal diameter.

Another important object of the present invention resides in the provision of a plug of the character described which can be inserted anywhere within the hollow core or which can be provided with means for retaining the plug at the two ends of the core.

The foregoing and other important objects of the present invention will become more apparent during the following disclosure and by referring to the drawings in which:

FIGURE 1 is an elevation partly in longitudinal section of a newsprint paper roll provided with three plugs in accordance with the invention;

3,115,959 Patented Dec. 31, 1963 FIGURE 2 is an end view of the core and plug in position therein;

FIGURE 3 is a longitudinal section of one end of the core and of the plug in position therein; and

FIGURE 4 is a perspective view of the plug in accordance with the invention.

In the drawings, the same reference characters indicate the same elements throughout.

Reference numeral 1 indicates a newsprint paper roll in association with which the plugs of the invention are used. However, the plugs may be employed for other types of paper rolls such as wrapping paper, and the like, wherein the end of the core must be protected against damage. The cores of the invention can be also used for rolls of other types of material having a core which must be protected. The core is indicated at 2 and normally consists of a cardboard tube on which the paper is wound. The ends of the core 2 are provided at the two ends thereof with a plug 3 in accordance with the invention in order to protect the core during handling and shipping of the paper roll 1. Eng 3 is preferably made of wood and has an external cylindrical surface 4. The inner end of the plug 3 is bevelled as shown at 5 in order to facilitate insertion of the plug 3 within the core 2.

In accordance with the invention, resilient members 6 protrude at the external surface of the plug 3 in order to resiliently engage the internal surface of the core 2. Members 6 consist of spring wires longitudinally curved and convex, having their intermediate portion spaced from the surface of the plug and having their ends bent back and forming pointed tips 7, said ends being driven into the mass of the plug 3.

In accordance with the main feature of the invention, the resilient wires 6 are disposed in accordance with an inclined plane with respect to the long axis of the plug 3 and are equally spaced around the periphery of the plug. Preferably, there is at least three wires 6 which form interrupted screw threads. One end 7 of the wire 6 is driven into the bevelled portion 5 of the plug while the other end is driven into the cylindrical surface 4 whereby the leading portion of the wire is recessed with respect to the cylindrical surface 4. Thus, screwing of the plug within the core 2 is facilitated. When the plug has been screwed in position, the portion of the resilient wire 6 protruding radially outwardly with respect to the cylindrical surface 4 produces a groove within the soft material of the core 2, the latter being preferably made of carboard. Thus, the plug is prevented from popping out of the core. If desired, the plug can be screwed until it has reached a position well within the core 2, as indicated at 3 in FIGURE 1, to reinforce the core in the center portion and additional plugs can be located at the two ends of the core as shown at 3 in FIGURE 1.

The plugs adapted to be positioned at the ends of the core are preferably provided with abutment members 8 in the storm of small metal plates of generally rectangular shape secured to the external end face of the plug and having their radially inner corners bent back and sharpened to form claws 9 adapted to be driven into the wood of the plug. The abutment plates '8 are further secured in position by means of a single nail 10 passing through the middle thereof and driven into the wood of the plug. The abutment plates 8 are radially disposed with respect to the plug and protrude radially outwardly from the external cylindrical face 4 thereof in order to abut against the end of the core 2, to thus prevent displacement of the plug inside the core.

Preferably the plug has an axial bore 11 of much smaller diameter than the plug for inserting a suitable tool serving to screw and unscrew the plug.

From the foregoing, it is obvious that the wires 6 form resilient means which produces grooves in and tightly engage the internal surface of the hollow core 2 and positively prevent displacement of the core despite the space which may exist between the internal surface of the core and the external surface 4 of the plug. For example, even if the diameter of the wood decreases by one quarter inch during drying, the resilient wires 6 will nevertheless firmly retain the core in position.

The cores are positioned by rotating the same and are removed by rotating the same in the opposite direction. Because the resilient wires 6 are disposed in planes almost perpendicular to the long axis of the plug, the latter can be made with a minimum length and therefore a substantial economy of wood is obtained as compared to the plug described and claimed in the above noted US. patent.

While a preferred embodiment in accordance with the invention has been illustrated and described, it is understood that various modifications may be resorted to Without departing from the spirit and scope of the appended claims.

What I claim is:

1. A plug adapted to be inserted within a tubular core made of relatively soft material, said plug composed of a cylindrical solid Wooden body having an axial bore, and of a plurality of resilient elongated elements spacedly disposed around said body and having their ends secured to the external surface of said body and each said element disposed in a plane inclined with respect to the long axis of said body in order that said elements form interrupted screw threads, each element being curved radially outwardly between its secured ends so as to have its middle part spaced from the external surface of said body and protrude therefrom for producing a groove into and resiliently engaging the inner surface of said core and maintain the plug in position within the hollow core despite variations in the external diameter of said plug and the internal diameter of said core.

, 2. A plug as claimed in claim 1, wherein one end of said body is bevelled to form a tapered surface and a cylindrical surface adjacent said tapered surface, said resilient elements having one and secured to said tapered surface and the other end secured to said cylindrical surface.

3. A plug as claimed in claim 2, wherein said elements are metallic spring wires.

4. A plug as claimed in claim 3, wherein the ends of said wires are bent back and have pointed tips driven into the wood of said body.

5. A plug as claimed in claim 1, further including abutment members secured to the outer end face of said body and protruding from the external surface thereof in order to abut against the end of said core.

6. A plug as claimed in claim 5, wherein said abutment members consist of plates nailed to the end face of said body and having inturned claws at the inner corners thereof driven into the wood of the plug body.

7. A plug as claimed in claim 1, wherein said elements are metallic spring wires.

8. A plug as claimed in claim 7, wherein the ends of said wires are bent back and have pointed tips driven into the wood of said body.

9. A plug as claimed in claim 8, further including abutment members secured to the outer end face of said body, and protruding from the external surface thereof in order to abut against the ends of said core.

10. A plug as claimed in claim 9, wherein said abutvment members consist of plates nailed to the end face of said body and having inturned claws at the inner corner thereof driven into the wood of the plug body.

References Cited in the file of this patent UNITED STATES PATENTS 996,510 Oltsch June 27, 1911 1,809,267 Cushing June 9, 1931 1,861,294 Bartlett May 31, 1932 2,474,657 Corson June 28, 1949 2,537,184 Dunn Jan. 9, 1951 2,985,292 Beaudoin May 23, 1961 

1. A PLUG ADAPTED TO BE INSERTED WITHIN A TUBULAR CORE MADE OF RELATIVELY SOFT MATERIAL, SAID PLUG COMPOSED OF A CYLINDRICAL SOLID WOODEN BODY HAVING AN AXIAL BORE, AND OF A PLURALITY OF RESILIENT ELONGATED ELEMENTS SPACEDLY DISPOSED AROUND SAID BODY AND HAVING THEIR ENDS SECURED TO THE EXTERNAL SURFACE OF SAID BODY AND EACH SAID ELEMENT DISPOSED IN A PLANE INCLINED WITH RESPECT TO THE LONG AXIS OF SAID BODY IN ORDER THAT SAID ELEMENTS FORM INTERRUPTED SCREW THREADS, EACH ELEMENT BEING CURVED RADIALLY OUTWARDLY BETWEEN ITS SECURED ENDS SO AS TO HAVE ITS MIDDLE PART SPACED FROM THE EXTERNAL SURFACE OF SAID BODY AND PROTRUDE THEREFROM FOR PRODUCING A GROOVE INTO AND RESILIENTLY ENGAGING THE INNER SURFACE OF SAID CORE AND MAINTAIN THE PLUG IN POSITION WITHIN THE HOLLOW CORE DESPITE VARIATIONS IN THE EXTERNAL DIAMETER OF SAID PLUG AND THE INTERNAL DIAMETER OF SAID CORE. 